1. Field of the Invention
The present invention relates to female terminal parts mated with a male terminal of an electric connector, and more specifically to female terminal parts composed of a square cylindrical electric terminal body and a plate spring piece assembled with each other.
2. Description of the Related Art
FIG. 1 shows a conventional female terminal parts disclosed in Japanese Published Unexamined Utility Model Application No. 64-12383. The female terminal parts 1 are composed of a terminal body 7 formed with a square cylindrical electric contact portion 3 at one end thereof and a wire connecting portion 5 at the other end thereof, and a plate spring piece 9 assembled within the electric contact portion 3 separately. Further, the electric contact portion 3 of square cylindrical shape is formed with a bottom plate portion 11; two opposing side plate portions 13 and 15 bent upward at both sides of the bottom plate portion 11, respectively; and two opposing half top plate portions 17 and 19 further bend inward at both ends of the side plate portions 13 and 15, respectively. Further, two square-shaped lug engagement holes 21 are formed on the side plate portions 13 and 15 beginning from the bottom plate portion 11, respectively. On the other hand, the plate spring piece 9 is formed with two lug portions 23 on both sides thereof on one end thereof. Therefore, the female terminal parts 1 can be assembled by engaging the two lug portions 23 of the plate spring piece 9 with the two lug engagement holes 21 formed in the two side plate portions 13 and 15 of the electric contact portion 3 of the terminal body 7.
FIGS. 2A to 2J are views for assistance in explaining the manufacturing process of assembling the female terminal parts automatically in a mass production line. First, as shown in FIGS. 2A and 2B, the electric contact portion 3 is half bend; that is, the two side plate portions 13 and 15 are half (a predetermined angle) bent relative to the bottom plate portion 11 and further the two half top plate portions 17 and 19 are also half (another predetermined angle) bent relative to the two side plate portions 13 and 15, respectively. Under these conditions, as shown in FIGS. 2C and 2D, the plate spring piece 9 is inserted into an inner space of the electric contact portion 3 and mounted on the bottom plate portion 11 thereof. Further, as shown in FIGS. 2E, 2F, 2G and 2H, the two side plate portions 13 and 15 are further bent inward by additional two different steps to engage the two lug portions 23 of the plate spring piece 9 with the lug engagement holes 21 of electric contact portion 3. Lastly, as shown in FIGS. 2I and 2J, the two side plate portions 13 and 15 and the two half top plate portions 17 and 19 are further bent inward to complete the square-shaped electric contact portion 3. After the plate spring piece 9 has been assembled with the electric contact portion 3, the female terminal parts 1 thus assembled is mated with a male terminal parts (not shown).
In the above-mentioned automatic assembly process, as shown in FIG. 2D, it is necessary to determined a distance L1 of the opening space between the two half top plate portions 17 and 19 to be less than that L2 between two outer sides of the two lug portions 23 of the plate spring piece 9. Therefore, after the plate spring piece 9 has been mounted on the bottom plate portion 11, when an external force is applied to the electric contact piece 3 now having been assembled and thereby the electric contact piece 3 is vibrated, there exists a problem in that the mounted spring plate piece 9 is dislocated obliquely from the lug engagement holes 21 as shown in FIGS. 3A and 3B with the result that defective female terminal parts are inevitably produced in the automatic assembly line.